Patients will be stratified according to ACTG 388 treatment or non-ACTG 388 study participation. Patients will then be randomized to receive either a protease inhibitor (PI)-sparing regimen of 2 nucleoside reverse transcriptase inhibitors (NRTIs) with efavirenz (EFV) (Arm I) or an NRTI-sparing regimen of EFV with lopinavir/ritonavir (LPV/r) (Arm II). Arm I options are enteric-coated didanosine (ddI-EC) plus lamivudine (3TC), ddI-EC plus zidovudine (ZDV), ZDV plus 3TC (or Combivir), stavudine (d4T) plus 3TC, or ddI-EC plus d4T (with exceptions as noted in the protocol). Only LPV/r, EFV, d4T, and ddI are provided by the study; other medications are obtained by nonstudy prescription.